Electrically heated hose assembly for conveying electrically conductive liquids

Abstract

An electrically heated hose for providing heat only to the section of hose which contains an electrically conductive liquid therein includes a plurality of resistance heating elements positioned between inner and outer layers of electrically insulative material defining the hose wall and arranged to sectionalize the hose into individual independently heatable sections. Each heating element has a first terminal connected to a power source and a second terminal connected to at least one of a plurality of spaced electrically conductive members disposed on the inner layer and exposed to any electrically conductive liquid conveyed by the hose. A continuous electrical conductor exposed to any liquid in the hose extends along the entire length thereof in spaced relation to the plurality of conductive members and is connected the power source. The presence of electrically conductive liquid in a separate section of the hose provides electrical continuity between the continuous conductor and at least one of the conductive members in the section to energize at least one heating element associated with the section. The conductive members and conductor are arranged so that the deeper the conductive liquid in a hose section the greater the number of heating elements activated by the liquid.

What is claimed: 
     
       1. A hose assembly comprising: a hose member for conveying an electrically conductive liquid therethrough, said member including an outer layer of material and an inner layer of electrically insulative material, said inner layer of electrically insulative material forming a cavity for conveying said electrically conductive liquid;   a first electrically conductive member positioned within said cavity so as to be exposed to any electrically conductive liquid conveyed by said hose member and extending as a continuous member along substantially the entire length of said hose member;   means for operatively connecting said first electrically conductive member to a first terminal of a power source;   a plurality of heating elements having a first terminal and a second terminal with at least one of said plurality of heating elements being positioned in a separate section of predetermined length of said hose member along the length of said hose member to independently provide heat to each separate section, said plurality of heating elements being positioned between said outer and inner layers of material of said hose member;   means for operatively connecting said first terminal of each of said plurality of heating elements to a second terminal of the power source;   a plurality of second electrically conductive members with at least one of said plurality of second electrically conductive members being positioned within the cavity in each separate section of hose member of predetermined length and positioned so as to be exposed to any electrically conductive liquid conveyed by said hose member; and   means for operatively connecting each of the at least one of said plurality of second electrically conductive members positioned in each separate section of hose member to said second terminal of each of the at least one of said plurality of heating elements positioned in each separate section of hose member,   whereby the presence of an electrically conductive liquid in a separate section of the hose member provides electrical continuity between the at least one second electrically conductive member in said section and said continuous first electrically conductive member to complete the electrical circuit to the at least one heating element in said separate section to cause heating of said separate section of said hose member.   
     
     
       2. The hose assembly of claim 1 wherein said inner layer of material comprises a heat radiating and sealing material. 
     
     
       3. The hose assembly of claim 2 further including a second layer of material positioned between said inner layer and said heating elements, said second layer of material comprising a heat radiating and embedding material. 
     
     
       4. The hose assembly of claim 3 wherein said heating elements are embedded in a third layer of material, said third layer of material comprising a high heat-conductive polymer material. 
     
     
       5. The hose assembly of claim 4 further including a fourth layer of material positioned between said third layer of material and said outer layer of material, said fourth layer of material comprising a heat radiating and embedding material. 
     
     
       6. The hose assembly of claim 5 further including a fifth layer of material positioned between said fourth layer of material and said outer layer of material, said fifth layer of material comprising a pressure containment layer embedded in heat reflective plastic. 
     
     
       7. The hose assembly of claim 6 further including a sixth layer of material positioned between said fifth layer of material and said outer layer of material, said sixth layer of material comprising a heat containment-reflective layer. 
     
     
       8. The hose assembly of claim 7 wherein said inner layer of material comprises a material treated for protection against abrasive wear from said liquid. 
     
     
       9. The hose assembly of claim 7 wherein said outer layer of material comprises a layer of a rubber compound treated for protection against abrasive wear. 
     
     
       10. The hose assembly of claim 1 further including a circuit breaker operatively connected between said means for operatively connecting said first terminal of each of said plurality of heating elements and said predetermined power source. 
     
     
       11. The hose assembly of claim 10 further including a thermostat assembly operatively connected between said circuit breaker and said power source. 
     
     
       12. The hose assembly of claim 1 wherein said plurality of heating elements comprises high resistance electrical wires. 
     
     
       13. The hose assembly of claim 1 wherein said plurality of heating elements comprises material exhibiting a positive temperature coefficient of resistance.